1. Field of the Invention
The present invention is related to a scroll compressor, specifically an improvement in sealing and lubricating between stationary and orbital scroll members of the compressor.
2. Description of the Related Art
A scroll compressor has a pair of stationary and orbital scroll members inside a sealed vessel, with plural compression chambers formed between them. Since these compression chambers are at high pressure, the orbital scroll member is inclined to be pushed away from the stationary scroll member. Consequently, a gap is formed between the scroll members, and leakage occurs between adjacent compression chambers. A method of preventing this is given in, for example, Japanese Utility Model Publication of Unexamined Application No. SHO-56-85087. In this method, high pressure gas forced out of a compression chamber is guided below the orbital scroll member, that is, to the side away from the stationary scroll member, and supports the orbital scroll member by pushing it against the stationary scroll member. In other words, the stationary scroll member is fixed to a frame inside the sealed vessel, while the orbital scroll member is pinched between this stationary scroll member and a protrusion integrally formed on the frame. Coolant gas which is sucked into the compression chamber between a stationary scroll member and an orbital scroll member from a suction pipe is compressed by the rotary motion of the orbital scroll member and so is brought to high pressure, and is forced out to the interior of the sealed vessel through the ejection port in the stationary scroll member. It will be noted that the interior of the scroll compressor is essentially divided into a higher pressure side exposed to the high pressure gas ejected from the compression chambers and a lower pressure side exposed to the suction gas.
The inside, that is, the center, of the frame protrusion contains the main rotation shaft of the orbital scroll member. High pressure gas is guided into it and reaches the same high pressure as the higher pressure side of the sealed vessel. This causes the orbital scroll member to be pushed upward against the resistance of the pressure inside the compression chambers, so that gaps do not occur between the orbital scroll member and the stationary scroll member. Then, to make the sliding of the orbital scroll member against the stationary scroll member smooth, lubricating oil sucked up by the pumping action of the main shaft in the vicinity of the rear surface of the orbital scroll member moves past the frame protrusion due to the pressure difference and enters the spaces between the scroll members.
However, only a slight amount of the lubricating oil adhered to the vicinity of the frame protrusion enters the lower pressure side due to the pressure difference while the lubricating oil which is sucked up by the pumping action of the main shaft in the vicinity of the orbital scroll member does not sufficiently enter the spaces between the scroll members, which are at low pressure, so that the spaces between the scroll members are neither sufficiently sealed nor sufficiently lubricated, causing the capacity of the pressure to drop.
For this reason, a configuration has been described in U.S. Pat. Ser. No. 4,522,575 in which lubricant is supplied directly to the compression chambers through a suction pipe. However, in this configuration, a separate means is needed to control the amount of lubricant.